Coaxial Architecture TreeandBranch Architecture Express Trunk HFC Architecture

Coaxial Architecture

Tree-and-Branch Architecture Express Trunk

HFC Architecture HUBS node Tap Customer Homes Businesses amp in building

Rural Network Other cable outputs Fiber Optic Headend Active Device (Node) Optics RX/TX Cable RF

Near Passive Network 11 26 14 29 Headend or Node Two-Way Tap Four-Way Tap Eight-Way Tap Directional Coupler Splitter 29 Optics RX/TX 24 LPI LPS 21 17

Passive Network 29 Headend or Node 26 23 20 17 17 11 Node Two Way Tap Four Way Tap Slope Equalizer 4

Sample Headend 1 Analog Video 55 -550 MHz 2 Way RF splitter Com 21 out 430 MHz 2 Way RF splitter HCX com. Controller 2 DT 815 Amp 5008 ET 2 3 EDFA Hub Public switch EDFA 2 RRX HUB Return TX 2 RRX DWDD Return TX DWDM

Connector Parts Boot Body Ferrule

Types of Connectors Biconic FC ST SC D 4

Optical Loss Example

Coaxial Plant Design and Operation Optical Transmitters and Receivers

Topics • Overview • Optical Transmitters • Optical Receivers • Units of Optical Power • Power Budget

Optical Transmitter and Receiver Input Electrical Signal Reproduced Electrical Signal Optical Fiber Transmitter Receiver

Optical Transmitter Drive Level RF Input Control Drive Level Test Point Optical Fiber Laser Optical Connect or

Optical Output Power Laser Drive Levels Clipped Output Laser Performanc e Curve Modulated Optical Output Current Threshold Current Input RF Bias Current

Optical Receiver Bias Voltage Fiber Optical Connector Test Point Photo Detector Pre Amp Post Amp RF Out

Units of Optical Power

Optical Power Equations d. Bm = 10 log m. W = inverse log (d. Bm/10)

+/-10 d. B Optical Power Table Optical Power (d. Bm) Optical Power (m. W) 30 1, 000 20 10 10 0 1 -10 0. 1 -20 0. 01 -30 0. 001

Power Budget Formula P b = T p - Rin where P b = the Power Budget T p = output Power of the Transmitter and R in = required input to the receiver

Optical Node System RF out NOR NRT

Optical Node Operation Post Amp Node/Amplifier Block Diagram RF to Light Converter L 20 d. Bm. V Pre Amp Attenuator Level Contr ol Tilt Generator Splitter Light to RF Converter H Post Amp H L to RF Post Amp Combiner H L -20 d. B Rf TP

Forward Optical Receivers/NOR’S RF Gain adjust 9 A pad Optical monitoring T/P Optical alarm -30 down Test Point

Diamond Net RF Module

Coaxial Plant Design and Operation Amplifier Technology

Topics • Semiconductor Configurations in CATV –Single - Ended Amplifier –Push - Pull Amplifier –Parallel - Hybrid Amplifier

Semiconductor Amplifier Configurations

Single - Ended Amplifier 2 nd Harmonic plus Noise

Push - Pull Amplifier

Parallel - Hybrid Amplifier Push Pull Stage Pin Pout Push Pull Stage ADVANTAGES: High Gain and Reduced Distortions

Coaxial Plant Design and Operation Amplifier Configurations

Objectives • Describe the most common amplifier configurations and discuss their usage. • Identify the components for each of the amplifier configuration and explain their functions and importance.

Forward Amplifier Characteristics

Amplifier Output Tilt 11 d. B of tilt @ 750 MHz

Attenuator Function 20 d. Bm. V 10 d. Bm. V 50 MHz 750 MHz

Equalizer Function Effect of Cable 20 d. Bm. V 10 d. Bm. V 50 MHz 10 d. Bm. V 750 MHz 0 d. B 10 d. B Combined Results 50 MHz Effect of Equalizer 20 d. B 50 MHz 750 MHz

Response Equalizer Examples of Peak to Valley Responses. With Response Equalizers Installed These are available in either bumps or traps

Equalizer Selection 20 d. B 12 d. B = 50 MHz 750 MHz 11 d. B Interstage Eq Set for desired Tilt @ Output = = 8 d. B 62 E 750/11 50 MHz Secondary Eq Set Additional Tilt 750 MHz 11 d. B

Low DC TP High Amplifier Block Diagram with ALSC / AGC Post Amp ALSC Optional Response Interstage Plug In Equalizer Slope Eq. Inter Stage Amp Dist EQ DC TP Pad Post Amp Shorting Stub to One Secondary or DC 4 -8 -or 12 DC TP High Manual Interstage Pre Amp Gain Adj. Atten. Low Input EQ High Input Atten Low High Pad

Forward Amplifier Characteristics

Forward Sweep SWEEP GEAR SYSTEM AMPLIFIER METER

Sweep System Requirements Fiber Optic Interconnect Sweep Transmitter Headend Combiner Fiber Transmitter Node AMP 1 Amp 6 Amp 5 Amp 4 Amp 3 Amp 2 Reference *The remaining amplifiers in the cascade are compared to the reference.

AFTRE ER BEFO Raw Sweep

Low Level Signal Telemetry

Coaxial Plant Design and Operation Frequency Response Specifics

Ideal Response 50 MHz Signal Level Non Linear Cable Loss Characteristics 550 MHz Non Linear 50 MHz Cable Kinks Z Mismatch 550 MHz

Hardware Points of Concern Connector Tap Cable Amplifier Cable Connector

Frequency Characteristics

Peak to Valley

Impedance Mismatch

RF Suckout

Low End Loss

Correcting the Characteristics of an Amplifier Signature

Correcting the Characteristics of an Amplifier Signature 54 750

Before

After

Forward Amplifier Characteristics

Forward Amplifier Characteristics Thermal Control (TGSC plug-in) Optional Test Point -30 d. B Resistive Atten. Downstream Input/ Upstream Output Test Point -30 d. B Resistive Automatic Gain Control(AGC series plug-in) Optional Equalizer Pre-Amp Post-Amp H Return Amplifier Module LER series plug-in Optional Return RF +24 VDC Test Point Power Supply Surge Arrestor Downstream Output/ Upstream Input L L L AC H AC +24 VDC Surge Arrestor Thru Power Plug

Forward Amplifier Characteristics 40 d. B gain +48/35. 5 29 d. B -0. 4 Needs a minimum of 8 d. BMv at 870 MHz Cable Losses @870 MHz= 1. 5 d. B/100 ft @50 MHz=0. 5 d. B/100 ft + 43. 1 d. Bm. V 33. 6 d. Bm. V Input= 11/17. 7 d. B +38. 0/31. 5 d. Bm. V 23 d. B -0. 6 d. B 300 ft= 4. 5 d. B@870 1. 5 d. B@50 Each port has 19/6. 5 d. Bm. V out 20 d. B 17 d B -1. 5 +32. 5/29 d. Bm. V 14 d B 2. 0 11 d B -3. 5 Each port has 15. 5/12 d. Bm. V out.

Network Operation and Maintenance Procedures

Coaxial Plant Design and Operation Intermodulation Distortions

Distortion Cause: Amplifiers VCC Fs 55. 25 MHz Fs Amp 110. 5 MHz F s+ 2 F s 2 nd Harmonic

Intermodulation Distortion

Distortions Cross Discrete Modulation Third Order 2 nd Order Distortion

Discrete Second Order Distortions B A 55. 25 MHz 121. 25 MHz 175. 25 MHz Carrier 1 Carrier 2 Active 120. 00 MHz Carrier 1 229. 25 MHz Carrier 2 Beat Product 230. 50 MHz A-B = Carrier 1 +/- Carrier A+B Beat Products 2

CSO Beats in a 77 Channel System N 60 COMPOSITE SECOND ORDER (CSO) U Subtraction Beats: M 50 CSO -F 1, -F 2, -F 3 B • E CSO( Single Amp. ) = CSO(Spec. ) + 2*(Rated Output 40 R Actual Output) O 30 F 68 + 2*(46 - 48) = B Addition Beats E 20 68 + 2*( -2 ) = CSO +F 1, +F 2, +F 3 A T 10 68 + -4 = S 50 64 d. Bc 100 200 300 400 Frequency in MHz 500 550

Discrete Third Order Carrier 1 Carrier 2 Carrier 3 Active Beat Product = Carrier 1 +/- Carrier 2 +/- Carrier 3

Composite Triple Beat Distortions

Cross Modulation Vide o Aura l Channel A Un-modulated Carrier Channel B Channel A with Cross Modulation from Channel B

Composite Triple Beat Multiple Amplifiers CTB#Amps = CTB 1 Amp - 20 log (#Amps) 2 Amplifiers CTB 2 Amps = 68 - 20 Log (2) CTB 2 Amps = 68 - 20 x. 3 CTB 2 Amps = 62 d. Bc This is true if all the amplifiers are identical. CTB is 20 Log because it is a voltage function.

Cross Modulation Calculation • XMOD ( Cascade ) = –XMOD ( Single ) - 20 Log ( N ) –where N is the number of amplifiers in cascade.